1. Field of the Invention
The present invention relates to circuit interrupters generally and, more specifically, to those kinds of circuit interrupters in which an interlock is provided to prevent the handle from showing that the interrupter is in the OFF disposition when, in fact, the contacts are welded closed.
2. Description of the Prior Art
Molded case circuit breakers and interrupters are well known in the art as exemplified by U.S. Pat. No. 4,503,408 issued Mar. 5, 1985, to Mrenna et al., and U.S. Pat. 5,910,760 issued Jun. 8, 1999 to Malingowski et al, each of which is assigned to the assignee of the present application and incorporated herein by reference.
It is necessary to give an indication to an operator of a circuit interrupter that the contacts thereof have not opened when an operation has been performed which would normally have resulted therein. The prior art provides such indication by preventing the handle from moving into a position indicating that the interrupter is in the OFF (contacts open) disposition when, in fact, the contacts remain closed. Unfortunately, the interlock mechanisms employed in the prior art to accomplish the foregoing have been unduly intricate.
It would be advantageous if an effective interlock mechanism existed that is relatively inexpensive and less complicated in operation. It would also be advantageous if the interlock mechanism remained effective during all operational conditions of the interrupter, and even after high current interruption has been performed.